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Airspeed indication failure

A wasp nest obstructed the Captain’s pitot probe after a short layover in Brisbane.

Etihad Airways Airbus A330 at airport gate. Source: ATSB

On 21 November 2013, after a flight from Singapore, an Etihad Airways Airbus A330, A6-EYJ landed at Brisbane airport and was taxied to the terminal. Approximately 2 hours later, the aircraft was pushed-back from the gate for the return flight to Singapore.

The captain rejected the initial take-off attempt after observing an airspeed indication failure on his display. The aircraft taxied back to the terminal where troubleshooting was carried out, before being released back into service.

During the second take-off roll, the crew became aware of an airspeed discrepancy after the V1 decision speed and the take-off was continued. Once airborne, the crew declared a MAYDAY and decided to return to Brisbane where an overweight landing was carried out.

Engineering inspection after the overweight landing found that the Captain’s pitot probe was almost totally obstructed by an insect nest, consistent with mud-dauber wasp residue.

Engineering inspection after the overweight landing found that the Captain’s pitot probe was almost totally obstructed by an insect nest, consistent with mud-dauber wasp residue. The pitot obstruction had occurred during the 2 hour period that the aircraft was on the ground at Brisbane and was not detected during troubleshooting after the initial rejected take-off.

The aircraft operator has changed its policy on the use of pitot covers. They are now required to be used on all transits at Brisbane Airport, regardless of ground time.

The aircraft manufacturer has amended its maintenance troubleshooting manual to increase the likelihood that a blocked pitot probe will be detected.

The airport operator has extended its wasp inspection and eradication program and reviewed and updated its Wildlife Hazard Management Plan.

In addition, CASA has drawn attention to the safety implications of mud wasp activity through several publications.

Safety message

Operators can minimise the risk of pitot probe obstruction by consistently using pitot covers even during short transit periods.

Standard operating procedures include the cross-checking of airspeed during the take-off roll. These checks are an important last line of defence in preventing an aircraft from becoming airborne with airspeed indication problems.

Read the investigation report AO-2013-212

 
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Last update 06 June 2016